Radiologic bone remodeling pattern around DCPD-coated, metaphyseal-loading cementless short stems in elderly patients

Comparison of 5-year postoperative results between standard-length stems and short stems in one-stage bilateral total hip arthroplasty: a randomized controlled trial

PURPOSE

Short stems have recently become popular in total hip arthroplasty. Previous studies aimed at elucidating the efficacy of short stems did not eliminate the influence of other factors aside from stem length. This study aimed to evaluate the usefulness of short stems compared with that of standard-length stems that have the same proximal morphology, surface coating, and material.

METHODS

This was a prospective randomized study comparing 5-year midterm outcomes in 29 patients who underwent one-stage bilateral total hip arthroplasty with short and standard-length stems inserted in each of the two femurs. Clinical, radiographical, and dual-energy X-ray absorptiometry outcomes were compared.

RESULTS

No significant differences were found in perioperative and radiographic characteristics (femoral neck anteversion, flare index, operation sequence, operation side, operation time, stem anteversion, and stem alignment). The number of joints with complications, appearance of radiopaque lines around the stems, or bone mineral density changed in stem regions 5 years postoperatively. However, greater micromotion of the stem was seen on the side of the short stem. Satisfactory improvement in hip function was seen on both sides.

CONCLUSION

Based on the 5-year midterm outcomes, both stems obtained satisfactory clinical outcomes despite the greater micromotion with short stems. Both stems attained bone ingrowth fixation. Moreover, the stems were not significantly different in terms of stress shielding; however, further long-term studies (> 5 years) are required to validate our findings related to stress shielding.

Short femoral stem in total hip arthroplasty: stable fixation and low complication rates in elderly patients

BACKGROUND

We present the result of our experience in using a short femoral stem in elderly patients (>70 years of age) compared to patients younger than 70 years.

METHODS

Data were prospectively collected on 138 patients who underwent 148 primary total hip arthroplasty (THA), with a conservative short stem between November 2010 and June 2014. The cohort was divided into 2 groups: the study group (group 1) comprised 57 patients (60 THA) over 70 years of age at the time of surgery, with a mean age of 75.4 years (range 70-87 years) and a mean follow-up of 26.7 months (range 9-48 months). The control group (group 2) comprised 81patients (88 THA) less than 70 years of age with a mean age of 57.4 years (range 33-69 years) and a mean follow-up of 27.3 months (range 9-54 months). Hip function in the 2 groups was compared preoperatively and postoperatively using the Merle D'Aubigne hip score (MD) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) score.

RESULTS

At the latest follow-up, 1 calcar fracture was reported in a 54-year-old patient in the control group, which required fixation with a screw and had a favourable outcome. No cases of clinical or radiographic loosening were reported.Clinical results showed no statistically significant differences between the 2 groups.

CONCLUSIONS

The use of the GTS conservative short stem in patients over 70 years old has shown very good results and low complication rates, comparable to those for patients younger than 70 years.

Three-Dimensional Analysis of the Contact Pattern between the Cortical Bone and Femoral Prosthesis after Cementless Total Hip Arthroplasty

The cementless stem Excia (B. Braun, Melsungen, Germany) implant has a rectangular cross-sectional shape with back-and-forth flanges and a plasma-sprayed, dicalcium phosphate dihydrate coating from the middle to proximal portion to increase initial fixation and early bone formation. Here, the conformity of the Excia stem to the femoral canal morphology was three-dimensionally assessed using computed tomography. Forty-three patients (45 hips) were examined after primary total hip arthroplasty with a mean follow-up of 27 ± 3 months (range: 24–36 months). Spot welds occurred at zone 2 in 16 hips and at zone 6 in 24 hips, with 83% (20/24 hips) of those occurring within 3 months after surgery. First- (n = 12 hips), second- (n = 32), and third- (n = 1) degree stress shielding were observed. The stem was typically in contact with the cortical bone in the anterolateral mid-portion (100%) and posteromedial distal portions (85%). Stress shielding did not progress, even in cases where the stems were in contact with the distal portions. The anterior flange was in contact with the bone in all cases. The stability of the mid-lateral portion with the dicalcium phosphate dihydrate coating and the anterior flange may have inhibited the progression of stress shielding beyond the second degree.